Dominating Vampire

When Dominating Vampire enters the battlefield, gain control of target creature with mana value less than or equal to the number of Vampires you control until end of turn. Untap that creature. It gains haste until end of turn.

Bloody Betrayal

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Pack's Betrayal

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. If you control a Wolf or Werewolf, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Bloodthirsty Adversary

Haste
When Bloodthirsty Adversary enters the battlefield, you may pay {2}{R} any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Bloodthirsty Adversary, then exile up to that many target instant and/or sorcery cards with mana value 3 or less from your graveyard and copy them. You may cast any number of the copies without paying their mana costs.

Swamp

Sanguine Spy

Menace, lifelink
{1}, Sacrifice another creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
At the beginning of your end step, if there are five or more mana values among cards in your graveyard, you may pay 2 life. If you do, draw a card.

Evelyn, the Covetous

Flash
Whenever Evelyn, the Covetous or another Vampire enters the battlefield under your control, exile the top card of each player's library with a collection counter on it.
Once each turn, you may play a card from exile with a collection counter on it if it was exiled by an ability you controlled, and you may spend mana as though it were mana of any color to cast it.

Mountain

Anje, Maid of Dishonor

Whenever Anje, Maid of Dishonor and/or one or more other Vampires enter the battlefield under your control, create a Blood token. This ability triggers only once each turn. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
{2}, Sacrifice another creature or a Blood token: Each opponent loses 2 life and you gain 2 life.

Falkenrath Pit Fighter

{1}{R}, Discard a card, Sacrifice a Vampire: Draw two cards. Activate only if an opponent lost life this turn.

Olivia's Attendants

Menace
Whenever Olivia's Attendants deals damage, create that many Blood tokens. (They're artifacts with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
{2}{R}: Olivia's Attendants deals 1 damage to any target.